Extension-ladder.



Patented May 23, 1911.

2 SHEETS-SHEET 1.

s I In: co. wunmmon. n. c.

R. B. SHAW.

EXTENSION LADDER.

APPLICATION FILED DEC. 16, 1909.

1n Mann's PITsRJ-cm, wAsnINmoN. D. c.

Patented May 23, 1911.

2 SHEETS-SHEET 2.

RYLAND B. SHAW, OF DECATUR, ILLINOIS.

EXTENSION-LADDER.

Specification of Letters Patent.

Patented May 23, 1911.

Application filed December 15, 1909. Serial No. 533,310.

To all whom it may concern:

Be it known that I, Bream) B. SnAw, a citizen of the United States,residing at Decatur, county of Macon, State of Illinois, have inventedcertain new and useful Iniprovements in Extension-Ladders, of which thefollowing is a specification.

This invention relates to certain improvements in extension ladders; andthe objects and nature of the invention will be readily understood bythose skilled in the art in the light of the following explanation ofthe accompanying drawings showing what. I now consider my preferredembodiment from among other formations and arrangements within thespirit and scope of my in vention.

The invention consists in certain novel features in construction and incombinations and arrangements as more fully and particularly set forthand pointed out hereinafter.

Referring to the accompanying drawings;

Figure 1, is a rear elevation of a portion of a step ladder embodying myinvention. Fig. 2, is a side elevation of said step ladder showing theextensions thereof lowered. Fig. 3, is a side elevation of the stepladder spread in operative position and showing the extensions thereofelevated. Fig. 4, is a detail top plan view of locking links of theladder and legs and the brace connecting the same. Figs. 5 and 6, aredetail views of the locking links of the legs and ladder, respectively.Fig. 7-, is a detail sectional perspective view of a portion of theladder.

The ladder proper is composed of a front, lower or main section, and arear or extension section.

The main section consists of the longitudinal side bars B, rigidlysecured together and supporting the treads B.

The extension section consists of a pair of parallel longitudinal sidebars A, supporting the treads a, and spaced a distance apart lesst-hanthe distance between the two bars B of the main section; and a pair oflongitudinal guide bars A, parallel with, and outside of and spaced adistance from the tread supporting bars A, and rigidly fixed thereto bycross bolts a or other suitable means. The front longitudinal edges ofguide bars A rest against and are parallel with the rear longitudinaledges of the side bars B, of the main section.

At their upper ends. the main section side bars B have guide loops C,rigidly see cured thereto and loosely encircling the guide bars A, andholding them in longitudinally sliding engagement with said bars B. Eachguide loop can consist of a U- shapcd metal plate fitting and secured tothe opposite side faces of a bar B with the closed or doubled endthereof extending rearwardly from the bar B, and loosely passing aroundthe bar A, to hold the same to the bar B. The bars A, are straight andsmooth-faced to permit the free longitudinal movement thereof throughthe guide loops or plates (3.

At a. point a distance below its upper end, or at a point intermediateits length, the main section is provided with a locking dcvice passingto the rear edge of the extension section to permit free upward movementof said section on the main section but to grip and wedge said extensionsection to the main section and against down ward movement thereon forthe purpose of locking said extension, at any point in its range ofmovement, against downward movement on the main section.

In the specific example illustrated, this locking device comprises astrong metal link D, extending from front to rear of the main andextension sections and at its front end arranged transversely of thefront edge of a main section side bar and pivotally confined thereto bya suitable clip (Z, whereby the link can swing vertically on its fronttransverse end as an axis. The link is provided with a transversegripping bar or portion d, arranged in rear of a longitudinal rear edgeof a bar of the extension section. This transverse gripping portion (1,is arranged a distance from the front axis on which the link swings,greater than the horizontal distance from longitudinal rear edge of anextension section bar to said axis. whereby the extension section can befreely drawn upwardly on the main section inasmuch as the link will bethereby swung up to the horizontal position. However, when the extensionsection is moved down on the main section the free end of the link willswing down and thereby drive its gripping portion (1, into said rearlongitudinal edge and press the extension section forwardly tightlyagainst the main section and thus so tightly lock and wedge the partstogether as to uphold the extension section in the desired position.

In the example shown, each gripping or looking link D, compriseselongated side bars and a front cross bar forming the link pivot and arear cross bar forming the gripping portion cl, and this link encirclesa main section side bar B, and an extension guide bar A, and thegripping bar cl, extends across the rear edge of the bar A. A pair ofthese links is provided, one for each pair of side and guide bars B, A.Suitable means are provided for connecting these two links to cause'themto swing together to act as one link or locking device. For in stance, Ishow the two ladder locking links connected by a cross member f,pivotally joined to the ends cl, of the links extended rearwardly beyondthe gripping bars cl, thereof, and by which the two locking links can beswung up to break their gripping hold on the extension section when itis desired to raise or lower the same.

lVhen the ladder is to be used as a step ladder, I provide an extensionleg consisting of a main or base section composed of rigidly connectedlongitudinal bars I), and an extension section at its upper endpivotally joined by cross bolt 9, to the upper end of the ladderextension member, and consisting of a pair of longitudinal bars a,arranged parallel with and resting longitudinally against the inner orfront edges of the bars I). At their upper ends, the bars I), have guideplates or loops 0, fixed thereto and loosely encircling bars a, toconfine the bars together in longitudinal sliding engagement.

Intermediate their lengths, the bars I),

are provided with vertically swinga-ble lockinglinks D, similar inconstruction-and operation to the links D, and loosely embracing thepairs of bars a, Z), respectively and pivotally joined to the bars I),so that their front free gripping ends traversing the front edges ofbars a, can swing vertically to and from gripping position. These linkslock and release the bars a, the same as described in connection withlinks D.

The two gripping links D, are connected to work in unison by crossmember f, and the two cross members f, f, can be pivotally joined at f",to form the step ladder brace, and at the pivotal point can be providedwith a handle E, for breaking the brace or folding the same upwardly aswill be readily understood by those skilled in the art.

What I claim is 1. In an extension ladder, in combination, a mainsection of side bars and treads, an extension section arranged paralleltherewith and adjustable longitudinally thereof and confined thereto andcomprising side bars provided with treads and outer-side longitudinalguide bars parallel with and spaced from the side bars and arranged insliding longitudinal engagement with the rear edges of said main sectionside bars, and a swingable wedging and locking device pivotally joinedto the main section bars and having transverse gripping portionstraversing the rear edges of said guide bars.

2. In an extension ladder, in combination, amain section of side barsand treads, an extension section arranged parallel therewith andadjustable longitudinally thereof and confined thereto and comprisingside bars provided with treads and outer-side longitudinal guide barsparallel with and spaced from the side bars and arranged in slidinglongitudinal engagement with the rear edges of said. main section sidebars, and a swingable wedging and locking device pivotally joined to themain section bars and having transverse gripping portions traversing therear edges of said guide bars, and comprising several links embracingthe pairs of main section bars and guide bars, respectively, and meansconnecting the rear free'ends of said links to raise the same in unison.

3. In an extension ladder, in combination, a main section of side barsand treads, an extension section of side bars and treads and providedwith outer-side guide bars spaced from said side bars, guides'fixed tothe upper end portions of said main section bars and loosely embracingsaid guide bars,

and several locking links embracing the pairs ofvmain sectionbars andguide bars, respectively, and at their front ends traversing andpivotally joined to the front edges of said main section bars and attheir rear end-s having gripping portions traversing the rear edges ofsaid guide bars, and means connecting the rear ends of said links tocause them to swing vertically together.

4. An extension ladder comprising a main ladder section, an extensionladder section confined to said main section in longi tudinal slidingadjustment, a leg at its up per end pivotally joined to the upper end ofsaid ladder extension section and comprising sections confined togetherin longitudinal sliding adjustment, vertically swingable gripping linksfor locking. said ladder sectionstogether and for locking. said legsections together, and a jointed vertically-folding brace between saidladder and leg and confined to and connecting said links,substantially'as described.

RYLAND B. SHAW.

lVitnesses JOHN L. KEIFER, RALPH S. BAUER.

Copies of this patent may be obtained for five cents eaoh,;byWashington, D. G.

addressing the Commissioner of Patents,

